The present disclosure relates to a control device that controls an inverter interposed between a DC power source and an AC rotary electric machine to perform power conversion between DC power and AC power.
An example of the control device described above is described in U.S. Pat. No. 6,163,127. U.S. Pat. No. 6,163,127 describes a technology for sensorlessly detecting the position (magnetic pole position) of a rotor without using a rotation sensor, the position being required to control drive of an AC rotary electric machine through vector control. In order to improve the efficiency and the accuracy of the system, the control device according to U.S. Pat. No. 6,163,127 is configured to switchably use one of a technique that is suitable to detect the magnetic pole position in a low rotational speed range and a technique that is suitable to detect the magnetic pole position in a high rotational speed range in accordance with the rotational speed of the rotor.
In the configuration in which the magnetic pole position of the rotor of the AC rotary electric machine is sensorlessly detected, in general, the magnetic pole position of the rotor is detected in a state in which the magnetic pole position of the rotor is unknown when the AC rotary electric machine is started from a state in which the AC rotary electric machine is stationary. Therefore, it takes a long time to detect the magnetic pole position compared to a case where a rotation sensor is used, which accordingly increases the time required to start the AC rotary electric machine. In U.S. Pat. No. 6,163,127, however, such an issue is not taken into special consideration.